1. Field of the Invention
The invention relates to a communicating method of a network which shares information, an information processing apparatus, and its control method.
2. Related Background Art
In recent years, providing of information using WWW (World Wide Web) has rapidly been spread. The user accesses various information which is provided by WWW, selects necessary information, and uses it.
In WWW, an information provider asynchronously and irregularly updates the information. Therefore, the user needs to actively access several Web servers in order to always obtain the latest information and confirm by himself whether new information has been added or not, the information which had been provided before has been changed or not, or the like.
In order to obtain information which the user requires an emergency such as information regarding discovery of a new type of virus or a security hole, information of new products which are registered into an auction site, and the like, it is necessary to access the Web server at the frequency according to the emergency, so that the user is burdened.
To reduce such a burden, a system in which update of the information on the Web site is detected and informed to the user exists conventionally. For example, in the system proposed in JP-A-10-171700, a WWW server itself detects update of a file on the server and informs the user of it. As proposed in JP-A-2001-67283, a system in which when a document registered by the user is updated, it is informed by mail, or the like exists.
However, according to the above conventional systems, since the system for detecting the update and informing is operated on one server, there is a problem such that in association with an increase in number of users, an excessive load is caused to the server to which a very large number of processes are unitarily concentrated. Further, there is a problem of weakness such that when the server for operating the system stops, all services are stopped.
On the other hand, in a system proposed in U.S. Pat. No. 5,978,842, there has been disclosed a method whereby the update detecting process is executed by an individual client who receives an update notification of the document and the server executes only the sum and notification of update detection results. According to such a method, it can be expected that an effect is exercised in terms of an object to reduce a load that is applied to the server. However, the processes regarding the notification are still concentrated on the server and an improvement regarding the weakness as mentioned above is not made yet.
In JP-A-06-314248, there has been disclosed a system in which when information of the own terminal is updated, each terminal in a group informs all terminals in the group that the information has been updated and exchanges the information. However, according to the system disclosed in JP-A-06-314248, since each terminal informs all of the terminals that the information has been updated, a load of the terminal in which the information has been updated is large and each terminal can share the information only together with the terminal with which each terminal can directly communicate.